I've wanted one for a long time, but haven't been able to find a nice one. Honestly, I'd love to have one that is in great condition, but not working, so that I could have the pleasure of rebuilding it. We'll see if I can ever get one...
I just got lucky on buying mine. Guy I bought it from I work with his son. I gave $400 for mine with scope. I also bought a Beeman P1 which is made by Weihrauch in great shape for $100 that same guy had. I sold it already.
I have had my 300S Running Target for maybe 30 years. I finally resealed it a couple years ago. Off the bench it has always been a one hole shooter @ about 10 meters.